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  • Phosphohexose isomerase/autocrine motility factor/neuroleukin/maturation factor is a multifunctional phosphoprotein.

Phosphohexose isomerase/autocrine motility factor/neuroleukin/maturation factor is a multifunctional phosphoprotein.

Biochimica et biophysica acta (2000-09-27)
A Haga, Y Niinaka, A Raz
ABSTRACT

Phosphohexose isomerase (PHI) is a member of the ectoenzyme/exoenzyme family and plays a key role in both glycolysis and gluconeogenesis pathways. Upon secretion PHI acts as a cytokine with tumor autocrine motility factor (AMF), neuroleukin (NLK) and maturation factor (MF) functions. Signaling is initiated by its binding to a cell surface 78 kDa glycoprotein (gp78). However, since PHI protein is a 'leaderless' secretory protein, released from cells via a non-classical route(s), we questioned whether the molecule undergoes post-translation modification while retaining proper folding and maintaining intact enzymatic and motogenic activities. To address this, we have generated, expressed and isolated a recombinant human AMF (rhAMF). The rhAMF retained the biological activities of the native AMF, i.e., catalyzes phosphohexose isomerization and stimulated cell motility. Additionally, we show here that human PHI is phosphorylated at serine 185 by casein kinase II (CK II) and we provide experimental evidence suggesting that this phosphorylation is associated with secretion, thus providing insights for elucidating the intracellular signal transmission of cell response to stimulation by AMF/NLK/MF.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Phosphoglucose Isomerase from Bacillus stearothermophilus, lyophilized powder, 300-1,000 units/mg protein
Sigma-Aldrich
Phosphoglucose Isomerase from baker′s yeast (S. cerevisiae), Type III, ammonium sulfate suspension, ≥400 units/mg protein (biuret)
Sigma-Aldrich
Phosphoglucose Isomerase from rabbit muscle, Type XI, lyophilized powder, ≥200 units/mg protein
Supelco
Phosphoglucose Isomerase from baker′s yeast (S. cerevisiae), for use with Fructose Assay Kit FA-20